hello i have the following control board for an ice maker
http://www.nt-ice.com/product.php?p=manitowoc_76-2907-3&product=170648

it is a straight forward board, its basically ic's controlling 3 relays.
one of the relays is for the ice makers compressor. that relay isn't getting proper power, one leg has jumping voltage and the other leg has nothing.

i desolered that relay and tested it, and it works fine.

im not an expert in circuits but i did know to check the corresponding the transistor. i plugged it into the voltmeter and it gave me a HFE value of 230, actually i tested all 3 (got them mixed up now) they gave values of 230, 220, 220, is that enough to say that the transistor is ok, or could it still be faulty? and cause what is happening?

3 NPN transistors MPSA05
3 SPST 24VDC relays
ic 1 - 18 pin unmarked
ic 2 - 93LC46 / I/p SCW / 9921 (Serial EEPROM?)
ic 3 - PM94BR / LM / 2904N

 

Hi seesoe, Is the compressor relay clicking on & staying on or chattering? Since in the picture of the board the 3 relays all look the same, i would try swaping the compressor relay with one of the others & see what happens. It does help to post sharp & clear pictures of you actual board you are trying to repair.

 

hi debe, thank you for the reply,

the information i was told was based off of what the refrigeration technician told me.

he actually said the whole board was bad, the relay for the compressor was doing funny things, and wanted to charge me $400 for a new board (it is really $300, the put a $100 markup on it) and another 150 to change it out.

so of course i told him no, and started tracing components from the relay to the ic and see what could be the issue, everything seemed fine. so i soldered everything back and hooked the board back to the ice maker and found out that the board was working perfectly and the compressor relay was clicking and providing power out just fine. i kept tracing the output of that relay, and found that it connects to an external (from the board) relay. it is a 120vac 18a spst relay, i found out it's coil went bad and no longer contacting. i quickly replaced it with a radioshack relay for a couple of buck and everything worked fine.

how about that?
thank again

 

Glad you fixed it, so if he replaced the board it still wouldnt have fixed the prob & cost you more!

 

exactly, probably another $200

 

Uh oh !!!.......I feel a bad attitude attack..............

Refrigeration "technician" huh ?? sounds like another one of those glorified part changers to me

One of the disciples of .......

" if you can't dazzle 'em with intelligence.........Baffle 'em with baloney"........

people like that should be slammin' burgers @ Mc Dumdums for min. wage.